Geomagnetic reversals have occurred frequently over the past 169 million years. Paleomagnetic evidence is found in rocks on the ocean floor and in some lava flows.

Geomagnetic polarity is shown (image right) as time descends back in time from present day (top) to the Jurassic period (bottom). Polarity has flipped between the normal configuration we observe today (black stripes) and the reverse configuration we observe in the paleomagnetic record (white stripes).

The Cenozoic era ranges from present day to 66 million years ago. The Mesozoic era ranges from the beginning of the Cenozoic era to 252 million years ago. The Cenozoic, known also as the Age of Mammals, is derived from a composite of the Greeks words for new and life.

The side-length naming threshold has the unintended consequence of leaving massive, roundish-shaped icebergs unnamed. An unnamed 64 square mile iceberg was spotted three weeks ago adrift in the South Atlantic Ocean.

What's in a name? That which we call a roseBy any other name would smell as sweet.

She asks what's in a name because the star-cross'd lovers are burdened with names from two warring families. Juliet laments a person's name is an artificial — and in their case, an irrelevant — convention.

Why do humans name things?

Naming is conventional and arbitrary. Naming objectifies. Naming gives us the illusion of control and the illusion of mastery over — or separateness from — the natural world.

Yet what would we do without naming? The negative aspects of objectifying things also grease the skids for interpersonal communication. Naming gives us a hand-hold on the abstract, the complex, and the poetic.

Naming gives us a handle to things. A personified handle is expressed in this passage from Anne of Green Gables:

Anne:

What is the name of that geranium on the window-sill, please?

Marilla:

That's the apple-scented geranium.

Anne:

Oh, I don't mean that sort of a name. I mean just a name you gave it yourself. Didn't you give it a name? May I give it one then? May I call it—let me see—Bonny would do—may I call it Bonny while I'm here? Oh, do let me!

Marilla:

Goodness, I don't care. But where on earth is the sense of naming a geranium?

Anne:

Oh, I like things to have handles even if they are only geraniums. It makes them seem more like people.

Saturday, December 13, 2014

If Earth's primordial water was boiled off from the intense heat during planetary cooling, where did Earth's abundant water originate?

The origin of Earth’s water remains a mystery.

A prevailing hypothesis is that Earth's water came later from collisions with water-bearing comets or proto-planets from the outer reaches of the Asteroid Belt

Recent analysis of the composition of water sampled on comet 67P suggest Earth's water might not have come from cometary collisions (Life from Comet Collisions).

Scientists suggest that one key to solving the mystery of Earth's abundant water is found in the D/H ratio or the flavor of water. The D/H ratio is the proportion of Deuterium (symbol D) to Hydrogen (symbol H). The ratio of these two hydrogen isotopes might provide clues to the origin of Earth's water.

Deuterium is a form of hydrogen (i.e., hydrogen isotope) that has an additional neutron not present in common hydrogen. There are about 6,420 hydrogen atoms for every deuterium atom found in the world's oceans.

Deuterium can replace hydrogen in water molecules. The properties of D2O differ from H2O (common water). D2O is called heavy water because it's 10.6% denser than H2O. D2O is also more viscous than H2O.

The current opinion that science and poetry are opposed is a delusion. On the contrary science opens up realms of poetry where to the unscientific all is a blank. Those engaged in scientific researches constantly show us that they realize not less vividly, but more vividly, than others, the poetry of their subjects.
― Herbert Spencer, Education, Intellectual, Moral, and Physical (1861)

Analysis of the composition of water sampled on comet 67P, along with previous D/H analysis of other comets show a range of ratios generally containing higher amounts of deuterium than Earth.

Of the 11 comets for which measurements have been made, it is only the Jupiter-family Comet 103P/Hartley 2 that was found to match the composition of Earth’s water.

The D/H ratio of water sampled on comet 67P is three times greater than that of Earth's oceans.

Scientists are are turning their attention to asteroids. Meteorites from asteroids in the Asteroid Belt have a closer match to the D/H ratio of water on Earth. Meteorites have a much lower water content than comets. However multiple serious of meteorite bombardments could have produced Earth's oceans.

Water does not resist. Water flows. When you plunge your hand into it, all you feel is a caress. Water is not a solid wall, it will not stop you. But water always goes where it wants to go, and nothing in the end can stand against it. Water is patient. Dripping water wears away a stone.
― Margaret Atwood, The Penelopiad

Gravitational pull varies by location because of unevenly distributed mass in the oceans, continents, and deep interior. Climate-related variables, like continental water balance, and the accumulation or ablation of glaciers, causes the distribution of mass to vary over time.

Measuring G-Force

The local gravitational field is measured using a gravimeter. A gravimeter is an accelerometer that measures the earthward acceleration of gravity or G-force.

Gravity Potato

Variations in Earth's gravity field is shown in an image known as the Potsdam Gravity Potato. The Potsdam Gravity Potato is derived from a gravity field model produced by the German Research Center for Geophysics (GFZ).